Spark plug



Dec. 20, D, C, SM|TH ET AL SPARKPLUG Filed Du. 27, 1929 A Homey PatentedDec. Z0, 1932 UNITED STATES PATENT orifice-- y y DAVID C. SMITH ANDWALTER PATE WALDEN, F SHREVEPORT, LOUISIANA SPARK PLUG Application ledDecember 27, 1929. Serial No. 416,845. l

This invention relates to an improved spark plug for use in connectionwith internal combustion motors and it has more particular reference tothe type of plug embodying a plurality of spark gaps for intensifyingthe spark and increasing the efficiency of the motor.

In carrying the' invention into edect we have evolved and produced anovel arrangeio ment of details cooperating in providing a plug which ischaracteristic in design, susceptible of easy and accessible cleaning,and

otherwise equipped for fulfilling the require-y ments of a product ofthis class in a highly satisfactory manner.

In the drawing:

Figure 1 is a view in section and elevation showing one form of theinvention.

Figure 2 is a view showing a slightly different form of the invention.

Figure 3 is a bot-tom plan view of Figure 1.

Figure 4 is a bottom plan view of Figure 2.

In Figures 1 and 3 reference character 5 Vdesignates the body of theplug-which includes the usual screw-threaded skirt portion 6. In thepresent instance we provide a retaining plate 7 which is fitted on thelower end of this skirt 6 and holds in place a mica diaphragm 10 whichserves to close the chamber 8 to prevent the accumulation of carbon andsoot therein.

The lower end portion of the insulator is designated at 9 and it will beobserved that this is of tapered configuration, and the bottom thereofrests firmly upon and contacting with the central portion of the micadiaphragm 10 held in place by the ring 7. The electrode is shown asprovided with a lat erally directed extremity 11, and this is "10 spacedfrom a contact button 12, the button being arranged for cooperation withthe secondary electrode 18. This electrode is shown as provided with alaterally directed end portion 14 spaced from the periphery of thebutton 12. Thus the end 11 of the main electrode is located on one sideand the end 14 of the secondary electrode is located on thediametrically opposite side of the button 12, thus forming two sparkgaps operable in an "0 evident manner for intensifying the sparks.

In Figure 2, reference character'l designates the bodyT and 16 thescrew-,threaded skirt defining` the chamber 17. Here the chamber isclosed by a mica diaphragm 18 held in place by a screw-threadedretaining ring 19. The insulator 20 is of cylindrical design andsomewhat larger in diameter and bears firmly upon the central portion ofthe diaphragm and carries the. electrode whose end portion is directedlaterally as at 21. `e0

The `contact button is indicated at 22 and is carried by the micadiaphragm to locate it close to the insulator 20 and in spaced relationfroln the laterally directed terminal 23 of the secondary contactorelectrode 24 which as o5 obvious is mounted on the shell or skirt 16.The principle is the same in that the terminal 21 and terminal 28 formspark gaps on diametrically opposite sides of the disc-like head of thebutton 22, thereby intensifying the A spark in an obvious manner.Incidently the terminals 21 and 23 ma lie 1n intimate contact with theunderside o the diaphragm or in spaced relation with respect thereto asshown in kFigure 1.

A careful consideration of the description iny connection with thedrawing will enable the reader to obtain a clear'understanding of theconstruction, arrangement, and features. Therefore, a more lengthydescription is re- ,80 garded as unnecessary.

Minor changes in shape, size, and rearrangement of details fallingwithin the scope of the inventionclaimed may be resorted to in actualpractice if desired.

We claim:

A spark plug of the class described comprising a shell, a thin disk ofmica having its edges abutting the lower end of the shell, a retainingring on the lower end of the shell .V90 holding the disk in place, abody of non-conducting material carried by the shell and having itslower end contacting the upper face of the disk, a main electrodepassing through the body and through a centrally ar- ,95 ranged hole inthe disk with its end bent `at right angles over the outer face of thedisk, aground electrode connected to an inner wall of the shell passingthrough a hole in the disk and having its outer part bent Vat ,.190

right angles over the outer face of the disk, and a button carried bythe disk and arranged between and spaced from the extremities of themain and ground electrode to form a pair 5 of spark gaps.

In testimony whereof We aiix our signatures.

sofv

DAVID C. SMITH.

